I think you've answered the question by mentioning the boat size and Tuna.
There will probably be no chair involved, meaning standing up while attempting to boat very aggressive and possibly large fish.
So that for me would mean standup gear, meaning a shorter rod designed for that purpose.
As for the reel, the one you've been using would work as would others of a similar size.
Since you have already been there, id think you know whats needed.
